matematika

 Modus


Observations cluster mode is the value that occurs most often or that have the highest frequency. Mode does not always exist, this is when all the observations have the same frequency occurs. For specific data, there may be some high frequency, and in such cases we have more than one mode.


example:
Contributions from Bogor on the National Red Cross listed as follows: Rp 9,000, Rp 10,000, Rp 5,000, Rp 9,000, Rp 9,000, Rp 7,000, Rp 8,000, Rp 6,000, Rp 10,000, Rp 11,000. So the mode, ie the value that occurs with the highest frequency, is $ 9,000.

Of the twelve high school students were taken randomly recorded how many times they watch movies over a month ago. The data obtained are 2, 0, 3, 1, 2, 4, 2, 5, 4, 0, 1 and 4. In this case there are two MODU, namely 2 and 4, because 2 and 4 contained the highest frequency. Such distributions bimodus said.

To find the mode of the data that has been compiled in the form of the frequency distribution of class first determined the modal class. Mode class is a class that has the highest frequency, then use the specified mode value formula:


Modus

B1 = lower limit of modal class.
d1 = The difference between the frequency of the mode with the frequency of the class preceding class.
d1 = The difference between the frequency of the mode with the frequency of the class the next class.
c = width mode classes.

 Median

The median is a measure of concentration that is often used. The median of a cluster of data that has been sorted from the smallest to the largest or from largest to smallest observation is right in the middle when the number of observations is odd, or the average of the two observations in the middle even when the number of observations.

example:


Of the five times the quiz statistics, a student receives a grade 82, 93, 86, 92, and 79. Determine the median population.
answer: Once the data compiled from the smallest to the largest, gained
             79 82 86 92 93
             Therefore, the medium was 86

Kada nicotine derived from a random sample of six cigarettes a certain cap is 2.3, 2.7, 2.5, 2.9, 3.1, and 1.9 milligrams. Determine the median.
responsibilities: If levels of nicotine were sorted from the smallest to the largest, it is obtained
           1.9 2.3 2.5 2.7 2.9 3.1
           So the median is the average of 2.5 and 2.7, ie

It also can be searched median of the data that has been arranged in the form of a frequency distribution. The formula used twofold


Where:
Bbk = lower limit of median class
c = width of class
s = The difference between the median frequency number with the cumulative frequency of the classes in the classroom median
fm = frequency of median class

Where:
Bak = upper limit of the median class
c = width of class
s' = the difference between the median frequency number frequency median cumulative grade
fm = frequency of median class

Before using the second formula above, must first be determined that the median class grade. Median class is the class that contains the number of median frequency, median frequency and the number is determined by dividing the overall data by two.

Consider the table below, we'll find above the median in both ways

By using both the above formula obtained: